Conventional load balancing mechanisms are used by a worker to handle equipment such as heavy air driven tools or to aid in placement for mounting of parts in assembly line type operations, etc. These load balancing mechanisms supply supporting forces in a vertical direction to counter gravitational force for supporting a given load and also structure to resist torque and vibration associated with certain tool operations. Typical load balancing mechanisms include a two-piece articulated arm of a straight cross section pivotally connected to a support post about which the arm is rotatable. The arm is pivotal for movement in a vertical plane and also rotatable about an axis of rotation horizontally displaced from an axis of the support post. A hinged connection allows the two sections of the arm to be selectively moved by a worker for placement of a load located at a distal end of one of the arms within the reach of the articulated arm.
In this conventional arrangement of the load balancing mechanism, deflection is created in the support post by the weight of the arm. This deflection is increased by the application of a load on the arm. This deflection establishes a "home" position, due to the combined effect of deflection of the axis of rotation and the axis of rotation being displaced from the axis of the support post, which is at a lowest elevational position for the arm about the post. The arm drifts to this "home" position if left uncontrolled or unattended. This drift is further exaggerated by the hinged construction of the articulated arm and makes controlling the arm mandatory.
The straight cross sectional shape of the articulated arm also necessitates applying a greater lifting force to the arm to counter the weight of any given load applied to the end of the arm as the greatest bending movement occurs at the connection of the support post and arm.